1. Field of the Invention
The present invention relates to a demagnetizing device, and in particular to a demagnetizing device for audio, video, data or other magnetic recording and/or playback apparatus for demagnetizing a component in the apparatus, such as, for example, a sound head, a video head, an erase head, rollers or the like. Needless to say, however, the device is not limited to such use.
2. Discussion of the Prior Art
In audio and video recording and/or playback apparatus, such as, for example, apparatus of the type which is suitable for recording and/or playing back from a magnetic tape, it is usual to provide the magnetic tape in a cassette type housing. Such apparatus, in general, comprise a cassette receiving area into which the tape cassette is mounted for playing or recording. A sound head, a video head, an erase head, rollers for tape to pass over and the like are mounted either in or adjacent the cassette receiving area. Through normal use, magnetic charges tend to build up on these components in or adjacent the cassette receiving area, and in general, the build-up of such magnetic charges considerably reduces the quality of sound or vision reproduction. It has been found, in particular, that the build-up of a magnetic charge on the sound head can cause considerable reduction in the quality of sound reproduction.
Unfortunately, there is no known device which is capable of effectively and at the same time simply removing a magnetic charge from any of the components in or adjacent the cassette receiving area of such apparatus.
One such prior art device for demagnetizing the sound in a cassette tape recorder/playback apparatus comprises a cassette type housing engagable with the cassette receiving area of the cassette tape recorder player. A magnet is rotatably mounted in the housing, and is driven, in use, by the drive spindle of the apparatus being demagnetized. The magnet is arranged to rotate in front of the sound head, and is mounted on a rotatable shaft with the poles of the magnet extending radially outwardly on opposite sides of the shaft. Accordingly, as the shaft rotates the magnet, the sound head is alternatively subjected to the fields of the north and south poles of the magnet. It has been found that this device does not adequately demagnetize the sound head. It is not known precisely why this device fails, however, it is thought that by virtue of the fact that the sound head is alternatively subjected to north and south fields, demagnetization is prevented.
There is therefore a need for a demagnetizing device which overcomes these problems.